Research on Gravity Compensation of Six-Dimensional Force Sensor for Parallel Robots Equipped with Printing Machine Bushings

The assembly of the printing machine shaft sleeve requires the parallel robot to have accurate perception of the environmental contact force. This paper proposes a gravity compensation method for the parallel robot, which collects the data of the six-dimensional force sensor when more than or equal to 3 groups of parallel robots are in different poses, and uses feedforward The neural network predicts the error of the sensor system, uses the least square method to solve the load center of gravity, gravity and other parameters, and uses the attitude transformation matrix of the parallel robot to compensate the gravity of the six-dimensional force sensor to obtain accurate contact force/torque information. The gravity compensation experiment was carried out in the parallel robot experiment platform of the printing machine shaft sleeve. The relative error of the resultant force in the x-axis, y-axis and z-axis direction of the six-dimensional force sensor is 1.40%, and the relative error of the resultant torque is 2.28%, which proves the method. It has a good gravity compensation effect for parallel robots, and can accurately sense the load gravity, which lays the foundation for force control of parallel robots.